问题
I'm using chai-webdriver to test some Google Polymer components and whenever webdriver loads the Chrome browser it uses a default set of switches. In order for Polymer's Shadow DOM components to appear in the DOM tree, it seems I need to enable the "Show user agent shadow DOM" option in the dev tools, but this gets reset back to disabled every time selenium-webdriver loads Chrome. I could add this to the default switches in webdriver, but I can't find a switch for it in this list. Anyone know what the right command-line switch to use is?
来源：https://stackoverflow.com/questions/26126587/how-to-enable-show-user-agent-shadow-dom-in-chrome-using-a-command-line-switch